"In 2007, its founders were ranked as the second most generous philanthropists in the US, and Warren Buffett the first. As of May 16, 2013, Bill Gates had donated US$28 billion to the foundation."
He "donated" to his own charity which he and his wife controls.
But since you asked, about 5 years. His net worth was about $67 billion in 2013. Now it's about $95 billion.
He did a lot of bad things as well. Microsoft the Monopoly set back computing by many years and was one of the most destructive forces for the past 30 years.
Gates must be spending a lot of money on PR to get his sainthood.
I'm sure zuckerburg and bezos are going to set up their own family charity to avoid taxes and "do good" too. Doesn't make them saints.